The .inf file is part of the driver. I am not sure if they even bothered with an XP driver, since it is being phased out. If you plug it in to a Win 7 computer, it will probably work fine.
Also, you may need to manually install the drivers.
As I stated before, get Service Pack 3, as it has quite a bit more in it & will bring your puter up to the safest point before they cut support. Go to Control Panel, then Windows Updaye & then have it download updates. It seems, being that you are on SP2, either you have automatic updates turned off, or have not connected it to the internet in a while.
Ed